More or Less Monday, 29 October, 2007 BBC Radio 4, 1630 BST Listen to programme

More or Less returned on Monday, 29 October with a new series and a new presenter - Tim Harford.

"National: Scale of harmful middle class drinking revealed: Well-off towns hide their problem drinking at home." - The Guardian.

"Surrey Middle Class Top Drinking League" - The Evening Standard.

"Middle class are biggest abusers of alcohol" - Daily Telegraph.

These were just some of the newspaper headlines generated after the publication of a national drinking league table published earlier this month.

Some of Britain's most solidly middle-class towns - places like Guildford, Woking and Harrogate - were singled out as the areas with the highest levels of hazardous drinking.

Presenter Tim Harford spoke to Professor Mark Bellis, the director of the North West Public Health Observatory (one of the report's authors) about why those middle-class towns have been wrongly maligned.

And how much alcohol is too much?

Hazardous drinking is defined as the consumption of more than two bottles of wine per week for men and more than one-and-a-half bottles of wine per week for women.

Find out more about presenter Tim Harford

But how hazardous is hazardous? Tim Harford also spoke to Professor Robin Room about the new scientifically based draft guidelines on safe drinking which he has produced for the Australian government.

He has worked out the probability of dying an alcohol related death for different levels of alcohol consumption.

So, for example, a man who drinks one pint of beer a night from the age of 18 stands a one in 100 lifetime chance of dying from an alcohol related disease and one in 100 chance of dying from an alcohol related injury.

You can work out your own probability of chronic disease or an alcohol related injury by consulting the Australian guidelines. (Refer to links on the right-hand-side.)

Making millions from maths

If you want to earn millions in the City these days, it pays to be good at maths. We look at life as a "quant".

William Hooper has made millions from maths

London has become an international centre for the world's most talented mathematicians who come here to earn a fortune working for banks and hedge funds.

These financial number crunchers are known as "quants" or quantitative analysts.

The most successful quants will come up with mathematical formulae that make them and their employers literally millions of pounds per year.

They are highly secretive about their work, not wanting others to know the details of their systems. More or Less got a glimpse into their world.

We found out from David Harding, head of hedge fund Winton Capital Management, about what he looks for in a quant, and presenter Tim Harford, in a Hello magazine style spoke to one of the City's maths boffins, William Hooper, inside his beautiful home.

Weather Forecast

What is the chance of rain?

View examples of probabilistic charts

Does our poor grasp of probability mean we get the weather forecasts we deserve?

The Met Office is keen to introduce probabilistic forecasts for rainfall and temperature, so the public can make better weather-related decisions.

It says complex weather systems mean there will always be uncertainty in forecasting, and that uncertainty should be communicated.

For example, it says if a farmer knows that the "chance" of rain the weather forecaster is talking about is actually a 60% likelihood, not 10%, then they are in a better position to make decisions about bringing the animals in.

But the BBC says that although it is interested in the idea and is discussing it with the Met Office, it is concerned about conveying complex data to the audience.

It says probabilities around the 50% mark may appear like guesswork, when people are expecting a deterministic forecast. Ken Mylne, from the Met Office was interviewed and we made broadcasting history as weather presenter Nina Ridge read Radio 4's first probabilistic forecast.

Nina Ridge began weather presenting in 2001

After reading the forecast Nina Ridge said: "It's a lot of information in a very short space of time and it's a lot, particularly on radio, for people to take on board."

She used to be a maths teacher and on probability she said, people are often unsure what the percentages really mean: "There are big challenges in communicating it.

"And I was always quite surprised as to the difficulty people had in understanding the concept of it.

"It's one of those topics which you think is straightforward, and on the face of it, it can be - 90% is a very high chance of something happening, 10% is very low.

"But when you get to 50% what does that mean? Am I just saying I'm not really sure what the weather's going to be like today or tomorrow?

"Does it mean for half the day it's going to rain? So I think there are huge challenges.

"And of course presenting the weather we're talking about radio, television, online - there's a huge variety in what we're forecasting, and in the audience we're forecasting to as well."

Presenter: Tim Harford
Producer: Innes Bowen

BBC Radio 4's More or Less was broadcast on Monday, 29 October, 2007 at 1630 GMT.

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